检索结果-内蒙古大学图书馆

probability distribution functions for unit hydrographs with optimization using genetic algorithm

APPLIED WATER SCIENCE 2017年第2期7卷 663-676页

作者： Ghorbani, Mohammad Ali Singh, Vijay P. Sivakumar, Bellie Kashani, Mahsa H. Atre, Atul Arvind Asadi, Hakimeh Univ Tabriz Dept Water Engn Tabriz Iran Texas A&M Univ Dept Biol & Agr Engn Scoates Hall2117 TAMU College Stn TX 77843 USA Univ New South Wales Sch Civil & Environm Engn Sydney NSW Australia Univ Calif Davis Dept Land Air & Water Resources Davis CA 95616 USA Mahatma Phule Krishi Vidyapeeth Rahuri India

A unit hydrograph (UH) of a watershed may be viewed as the unit pulse response function of a linear system. In recent years, the use of probability distribution functions (pdfs) for determining a UH has received much attention. In this study, a nonlinear optimization model is developed to transmute a UH into a pdf. The potential of six popular pdfs, namely two-parameter gamma, two-parameter Gumbel, two-parameter log-normal, two-parameter normal, three-parameter Pearson distribution, and two-parameter Weibull is tested on data from the Lighvan catchment in Iran. The probability distribution parameters are determined using the nonlinear least squares optimization method in two ways: (1) optimization by programming in Mathematica;and (2) optimization by applying genetic algorithm. The results are compared with those obtained by the traditional linear least squares method. The results show comparable capability and performance of two nonlinear methods. The gamma and Pearson distributions are the most successful models in preserving the rising and recession limbs of the unit hydographs. The log-normal distribution has a high ability in predicting both the peak flow and time to peak of the unit hydrograph. The nonlinear optimization method does not outperform the linear least squares method in determining the UH (especially for excess rainfall of one pulse), but is comparable.

关键词： Genetic algorithm Least squares method Mathematica Nonlinear optimization probability distribution function Unit hydrograph

来源：评论

学校读者我要写书评

暂无评论

Probabilistic cellular automata simulation of microstructure evolution: the role of model parameters on precision and uncertainty

引用

MODELLING AND SIMULATION IN MATERIALS SCIENCE AND ENGINEERING 2025年第1期33卷

作者： Seyed-Salehi, Majid K N Toosi Univ Technol Fac Mat Sci & Engn Tehran *** Iran

Probabilistic cellular automata (PCA) is a widely used and cost-efficient method for simulating microstructural evolution. In this method, probabilistic state change rules determine the evolution of cell states at each time step. However, its stochastic nature introduces inherent uncertainty, leading to non-repeatable results. Most microstructural simulation studies assess the accuracy of simulations by comparing predicted results with experimental observations, neglecting uncertainties in mathematical models and algorithms. In this study, the precision and stochastic behavior of microstructure evolution in the PCA simulations were investigated. The probabilities of transformations of cell states at each time step were formulated, and discrete probability distribution functions (dPDF) were introduced to analyze the frequency distribution of simulation outcomes. The performance and consistency of these dPDFs were assessed by comparing statistical analyzes of PCA simulation results with dPDF predictions, revealing that the variance of simulation results is less than that of the binomial distribution function. Additionally, the effects of modeling parameters, such as model size, cellular resolution, and probability distribution of state changes in two- and three-dimensional PCA modeling, on the precision and reliability of simulation results were studied. In PCA models, simulation uncertainty inversely relates to the square root of model size. Furthermore, in 2D simulations, uncertainty is inversely proportional to the square root of the cellular resolution, while in 3D simulations, it is inversely proportional to the cellular resolution itself. These findings provide a simple and computationally efficient method for evaluating PCA simulation uncertainty and determining optimal simulation parameters, including model size, cellular resolution, and dimensionality.

关键词： probabilistic cellular automata probability distribution function uncertainty assessment microstructure evolution

来源：评论

学校读者我要写书评

暂无评论

A novel approach to wind energy modeling in the context of climate change at Zaafrana region in Egypt

引用

SCIENTIFIC REPORTS 2025年第1期15卷 1-20页

作者： Kamel, Bassem Khaled Abdelaziz, Almoataz Y. Attia, Mahmoud A. Khamees, Amr Khaled Ain Shams Univ Fac Engn Dept Elect Power & Machines Cairo Egypt Future Univ Egypt Fac Engn & Technol Cairo 11835 Egypt Ain Shams Univ Fac Engn Dept Engn Phys & Math Cairo Egypt

Global warming, driven by the excessive emission of greenhouse gases from the combustion of fossil fuels, has emerged as a critical environmental challenge which is considered as a motivation for this research. Where, the switch to sustainable energy sources is crucial because of the pressing need to slow down climate change and lower carbon footprints. Of all the renewable energy sources, wind energy is particularly important as a means of reducing carbon emissions from the generation of electricity. With the increase in the penetration of renewable energy resources in electrical power systems, the stochastic behavior of the renewable energy resources has to be taken into account for better analysis in power systems. However, the stochastic behavior of the renewable energy is also affected by the environmental conditions. In this context, The main objective of this paper is to present a novel wind energy modeling that includes the effect of ambient temperature on the wind turbine capabilities. This effect is presented as the de-rating curve for wind turbine output power to respect the thermal capabilities of the electrical components of the wind turbine. That's why this novel model is developed to consider the effect of ambient temperature to represent the practical limitations of wind turbines which wasn't considered by previous literature although the temperature has a siginicant impact on the wind turbine output power. In this Paper, Gamesa G80 wind turbine is used to perform the numerical analysis of the proposed new model. Moreover, Exponential distribution Optimizer (EDO), Aquila Optimizer (AO), and Equilibrium Optimizer (EO) algorithms are used to find various probability distribution functions (PDFs) parameters to model wind speed data from Zaafrana region in Egypt using Root Mean Square Error (RMSE) and Coefficient of Correlation (R<^>2) as judging criteria. In addition, real temperature data from the same site are used to validate the proposed model compa

关键词： Wind energy Wind turbines Temperature de-rating Wind speed modeling probability distribution function Exponential distribution optimizer (EDO)

来源：评论

学校读者我要写书评

暂无评论

probability distribution functions for service loads of frame scaffoldings

引用

BULLETIN OF THE POLISH ACADEMY OF SCIENCES-TECHNICAL SCIENCES 2021年第2期69卷

作者： Blazik-Borowa, Ewa Pienko, Michal Szer, Iwona Hola, Bozena Czarnocki, Krzysztof Lublin Univ Technol Fac Civil Engn & Architecture Nadbystrzycka 40 PL-20618 Lublin Poland Lodz Univ Technol Fac Civil Engn Architecture & Environm Engn Politech 6 PL-90924 Lodz Poland Wroclaw Univ Sci & Technol Fac Civil Engn Wybrzeze Wyspianskiego 27 PL-50370 Wroclaw Poland Lublin Univ Technol Fac Management Nadbystrzycka 38 PL-20618 Lublin Poland

The paper discusses service load measurements (weight of construction materials, small equipment and workers) conducted on 120 frame scaffoldings all over Poland in 2016-2018. Despite the fact that the scaffolding should ensure the safety of its users, most accidents on construction sites are caused by fall from height. Service loads are one of the elements affecting the safety of scaffolding use. On the basis of the studies, maximum load on one platform and maximum load on a vertical scaffolding module for one day were obtained. They were treated as the random variables of the maximum values. Histograms and probability density functions were determined for these variables. The selection of a probability distribution consisted in the selection of a probability density function by means of fitting curves to the study result histograms using the method of least squares. The analysis was performed for distribution Weibull and Gumbel probability density functions which are applied for maximum values of random variables. Parameters of these functions can be used for the purposes of the reliability analysis to calibrate partial safety factors in simulation of service load during the scaffolding failure risk assessment. Besides, the probability of not exceeding the standard loads provided for frame scaffoldings for 120 weeks was established on the aforementioned basis. The results of the presented research show that in Poland there is a high probability of exceeding the permissible service loads in one year and thus there is a high risk of scaffolding damage.

关键词： scaffolding service load extreme events probability distribution function safety

来源：评论

学校读者我要写书评

暂无评论

Investigating the use of probability distribution functions in reliability-worth analysis of electric power systems

引用

INTERNATIONAL JOURNAL OF ELECTRICAL POWER & ENERGY SYSTEMS 2012年第1期37卷 110-116页

作者： Dzobo, O. Gaunt, C. T. Herman, R. Univ Cape Town Dept Elect Engn ZA-7701 Rondebosch South Africa

The use of probability distribution functions to describe reliability-worth input parameters is fairly new compared to using average values. Reliability-worth indices of power systems are frequently calculated as average values and convey little information about risk In this paper beta probability distribution function was used to model time-dependent customer interruption costs as an input parameter to reliability-worth analyses of power systems. Time-sequential Monte-Carlo simulation technique that can handle time dependence of the input parameters was employed in the analysis. The results revealed that more information can be derived from the reliability-worth indices when probability distributions are used to describe the reliability-worth input and output parameters. (C) 2011 Elsevier Ltd. All rights reserved.

关键词： Business customers Customer interruption costs probability distribution function Reliability-worth

来源：评论

学校读者我要写书评

暂无评论

On probability distribution functions in turbulence. Part 1. A regularisation method to improve the estimate of a PDF from an experimental histogram

引用

PHYSICA D 1999年第1-2期132卷 111-132页

作者： Andreotti, B Douady, S Univ Paris 06 Ecole Normale Super Lab Plast Stat Lab CNRS F-75231 Paris 05 France Univ Paris 07 Ecole Normale Super Lab Plast Stat Lab CNRS F-75231 Paris France

The most common method to estimate a probability distribution function (PDF) from experimental data is to compute a normalised histogram. This approximation implicitly assumes that the PDF is smooth at the scale of one histogram bin. Usually, the normalised histogram is ill defined for the rarer events since the points are very scattered in that region. In order to increase the quality of the PDF estimate, the assumption that the PDF is smooth can be used explicitly. A specially designed regularisation method is constructed and tested on both synthetic and real turbulence signals. Using this procedure, the estimated PDFs are now smooth and well-defined up to the unique rarest event (the last histogram point). Among its direct applications, the method allows to get a better estimate of high order PDF moments and of PDFs convolution products. (C) 1999 Elsevier Science B.V. All rights reserved.

关键词： statistics probability distribution function turbulence

来源：评论

学校读者我要写书评

暂无评论

A class of probability distribution functions preserving the packing dimension

引用

STATISTICS & probability LETTERS 2011年第12期81卷 1782-1791页

作者： Li, Jinjun Zhangzhou Normal Univ Dept Math Zhangzhou 363000 Peoples R China

Necessary and sufficient conditions for packing dimension preservation under transformations which are distribution functions of random variables with Q-representation are given. (C) 2011 Elsevier B.V. All rights rese... 详细信息

关键词： Q-representation probability distribution function Packing dimension

来源：评论

学校读者我要写书评

暂无评论

Simultaneous numerical representation of soil microsite production and consumption of carbon dioxide, methane, and nitrous oxide using probability distribution functions

引用

GLOBAL CHANGE BIOLOGY 2020年第1期26卷 200-218页

作者： Sihi, Debjani Davidson, Eric A. Savage, Kathleen E. Liang, Dong Univ Maryland Appalachian Lab Ctr Environm Sci Frostburg MD USA Woods Hole Res Ctr Falmouth MA USA Univ Maryland Chesapeake Biol Lab Ctr Environm Sci Solomons MD USA

Production and consumption of nitrous oxide (N2O), methane (CH4), and carbon dioxide (CO2) are affected by complex interactions of temperature, moisture, and substrate supply, which are further complicated by spatial heterogeneity of the soil matrix. This microsite heterogeneity is often invoked to explain non-normal distributions of greenhouse gas (GHG) fluxes, also known as hot spots and hot moments. To advance numerical simulation of these belowground processes, we expanded the Dual Arrhenius and Michaelis-Menten model, to apply it consistently for all three GHGs with respect to the biophysical processes of production, consumption, and diffusion within the soil, including the contrasting effects of oxygen (O-2) as substrate or inhibitor for each process. High-frequency chamber-based measurements of all three GHGs at the Howland Forest (ME, USA) were used to parameterize the model using a multiple constraint approach. The area under a soil chamber is partitioned according to a bivariate log-normal probability distribution function (PDF) of carbon and water content across a range of microsites, which leads to a PDF of heterotrophic respiration and O-2 consumption among microsites. Linking microsite consumption of O-2 with a diffusion model generates a broad range of microsite concentrations of O-2, which then determines the PDF of microsites that produce or consume CH4 and N2O, such that a range of microsites occurs with both positive and negative signs for net CH4 and N2O flux. Results demonstrate that it is numerically feasible for microsites of N2O reduction and CH4 oxidation to co-occur under a single chamber, thus explaining occasional measurement of simultaneous uptake of both gases. Simultaneous simulation of all three GHGs in a parsimonious modeling framework is challenging, but it increases confidence that agreement between simulations and measurements is based on skillful numerical representation of processes across a heterogeneous environment.

关键词： CH4 CO2 DAMM DAMM-GHG greenhouse gas N2O probability distribution function soil microsite

来源：评论

学校读者我要写书评

暂无评论

Levy isometrics of the space of probability distribution functions

引用

JOURNAL OF MATHEMATICAL ANALYSIS AND APPLICATIONS 2011年第2期380卷 847-852页

作者： Molnar, Lajos Univ Debrecen Inst Math H-4010 Debrecen Hungary

In this paper we present the complete description of surjective isometrics of the space of all probability distribution functions on R with respect to the Levy metric. (C) 2011 Published by Elsevier Inc.

关键词： probability distribution function Levy metric Isometry

来源：评论

学校读者我要写书评

暂无评论

THE ANGLE-DEPENDENT REdistribution functionS RIII AND RIV - LINE ABSORPTION probability-distribution functionS AND REEMISSION COEFFICIENTS

引用

ASTROPHYSICS AND SPACE SCIENCE 1984年第2期106卷 299-307页

作者： MCKENNA, SJ The MITRE Corporation Bedford Mass. USA

The line absorption probability distribution functions and the reemission coefficients are derived for the non-coherent scattering functionsRIII andRIV. The appropriate line profile function forRIII is shown to be a simple Voigt function, while forRIV, the line absorption probability distribution function is more complex involving a linear combination of two Voigt functions and another more complex probability distribution. The structure of the reemission coefficients forRIII andRIV is then discussed.

关键词： distribution function probability distribution Linear Combination Line Absorption probability distribution function

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：